In colder regions of the globe electrical devices are used to heat automobile engines and interiors to facilitate engine starting and user comfort. Energy costs and conservation efforts have led to the widespread use of parking lot controls. These controls are designed to reduce energy consumption while still satisfying engine starting and user comfort constraints. Numerous algorithms have been devised to limit this consumption, ranging from simple timers to the most current proportional temperature controls (the colder it gets the more power is delivered).
Current parking lot controls are centralized, whereby all the loads of a parking lot are switched together on or off by a central contactor. Many inherent restrictions and limitations are imposed by this form of centralized control. Central contactor controls carry substantial installation and maintenance costs, with typical installation pay back periods in the order of five years or more. The longevity of mechanical contactors depend heavily on regular maintenance adding to operational costs.
Many lots impose a limit on power use for each vehicle. But since no adequate means of enforcement exists, it is left open to abuse. Often enough users abuse the set limits to trip the main breaker for a lot, inconveniencing all patrons. In addition, individual parking stall breakers are tripped due to temporary short circuits, overloads, etc. Since no feedback as to the presence of power is provided for users or maintenance personnel, this stall maybe without power for several days.
U.S. Pat. No. 5,521,838 by the present inventor issued May 28th 1996 discloses an apparatus for controlling and monitoring electrical automobile heating loads for the purpose of energy conservation. By fitting each outlet box (which controls two stalls) of a parking lot with a reprogramable microcontroller greater flexibility is realized. One novel feature included is the ability to detect each load as it is asserted or removed. This enables the device to delay delivery of power to a newly asserted load for sometime. By including apparatus for sensing current being delivered to each load another dimension in control is added. This enables the effective enforcement of power consumption limits for each vehicle, assisting in local demand power management. Maintenance costs are reduced and user service is increased by the detection of overloads or short circuits. Enabling these loads to be switched “off” before the associated breaker can trip. Added safety is provided by helping to prevent faulty loads from starting fires or damaging property. This apparatus enables the use of economical solid-state contactors for delivering power to attached loads, reducing maintenance costs and boosting reliability.
Feedback to patrons is provided by visual or auditory apparatus. In the case of visual feedback two light emitting diodes (LED's) are provided, one green the other red for each stall. As an example, when a user asserts a load the presence of power is identified by a quick flash of the green LED (load within acceptable limits) or the red LED is lit solidly (overload is rejected). For auditory feedback different tones identify load acceptance or rejection and the presence of power.
A bi-directional infrared data communication interface for communication with service personnel. From time to time general maintenance of parking lots are performed requiring power tools. To facilitate this whole parking lots are disabled with centralized controls. While with the present invention only required individual outlets need be disabled. With this data link operational modes and limits can be easily set and changed. Since this link is bi-directional the device can be used to collect operational data to be down loaded periodically at request.
An interface is provided to allow the microcontrollers program or firmware to be changed, making it field programmable. This increases the useful life and reduces manufacture costs. Useful life is increased by the fact the energy conservation algorithms can be kept up to date and customized to a particular application. Manufacturing costs are reduced by having to produce only one generic model. And by reprogramming the devices with self test and calibration routines, manufacture costs are further reduced.
U.S. Pat. No. 5,903,064 Norberg issued May 11th 1999 discloses communication from a vehicle mounted control unit to the an outlet control unit using signals communicated through the power cord and through the distribution network between the outlets to a central unit at a central power source. The communication is used to allow an alarm function on disconnection, authorization of use and billing. The outlet control unit can also detect state of charging. The system is connected using a series arrangement.
U.S. Pat. No. 4,532,418 Meese issued Jul. 30th 1985 discloses a combined battery charging system and parking meter for vehicles which allows billing using a charge card system.
U.S. Pat. No. 6,614,214 Pelegrino issued Sep. 2nd 2003 discloses a battery charging system for vehicles which allows billing using an optical reader.
U.S. Pat. No. 5,563,491 Tseng issued Oct. 8th 1996 discloses a combined battery charging system and parking meter which allows billing using a radio transmitter system.